1. Field of the Invention
The present invention relates to a reed with a plurality of juxtaposed reed dents the ends of which are affixed in a lower profiled bar, hereafter broadly called lower U-channel, to be mounted on a batten beam, and in an upper profiled bar, hereafter broadly called upper U-channel.
2. Description of the Related Art
When reeds of the above kind are used in airjet looms, reed dents are used which include a U-shaped recess between their upper and lower segments defining a filling guide channel.
It was found in practice that high weaving rates, i.e. weaving rates of about 1,000 fillings a minute or more will produce streaks in the fabric which renders the fabric as irregular.
The objective of the present invention is to create a reed of the initially cited kind which shall be appropriate for high weaving rates.
This problem is solved in that the reed dents are provided with a width of about 6 mm at least in a segment extending from the lower profiled bar and a width of about 4 mm in their upper segment.
The invention is based on the insight that at high weaving rates the fabric streaks are caused by the reeds which, at such rates, will incur dynamic reed dent oscillations. The reed dents are comparatively rigid in their lower zone as a result of their widening at this zone and as a result flexure, especially at filling beatup, is reduced and thereby also the resulting oscillations of the reed dents.
On the other hand the upper, comparatively narrow segment which is farther from the axis of rotation of the batten, is lightweight, and inertial forces arising from the to-and-fro batten motion and acting on this reed dent segment and the resulting flexures and oscillations will remain small. Accordingly reed dent oscillations are restricted on account of their comparatively rigid lower segment and comparatively lightweight upper segment.
In one embodiment of the invention, the front edges of the lower and upper segments of the reed dents are at least approximately aligned with a beatup edge in the zone of the said recess. In this manner the reed designed with these reed dents can be used as an alternative to a conventional reed without entailing substantial changes in the loom.
In a further embodiment of the invention, the reed dents comprise a substantially straight edge running between the upper and lower profiled bars and located opposite the filling guide channel. This design offers the advantage that during assembly the reed dents can rest on this edge.
In a further embodiment of the invention, the reed dents have a wedge-shaped width, hereafter called tapering width, in that segment or segment portion where they enter into the lower or upper profiled bars, the cross-section of the lower and/or upper profiled bar matching said taper shape. This design of the invention offers the advantage that the outer contour of the lower profiled bar is not changed relative to conventional reeds and that it is very easy to use a reed of the invention as an alternative to conventional reeds without further changes in the loom. This design also allows forming reeds with comparatively wide reed dents having a straight front and rear edge which are recommended for high-rate weaving and/or to weave heavy fabrics. In this instance as well said wide reed dents can be used without entailing significantly changing the width of the lower profiled bar. In particular the same fasteners may be used to affix reeds having reed dents of different widths to the same batten beam.
Further features and advantages of the invention are elucidated in the description below and in relation to the embodiment shown in the drawing.